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Minerals

Bicarbonate: diabetic ketoacidosis, diarrhoea and the acid-base balance

According to MedlinePlus, the body makes carbon dioxide as a waste product of metabolism, turning food into energy, and according to the NVKC its main form is bicarbonate (HCO3-). According to the NVKC, carbon dioxide is needed to keep the ratio between acid and base in the blood in balance.

According to MedlinePlus, too little CO2 in the blood may be a sign of diabetic ketoacidosis, a complication of type 1 and type 2 diabetes. Only a blood test shows how much HCO3- is in the blood.

Diagnostiek voor U sets the limits for bicarbonate at 21 - 28 mmol/L, Star-SHL at 20 - 31 mmol/l.

Doctor's Assessment Included

According to the NVKC, bicarbonate (HCO3-) is the main form of carbon dioxide in the body. The kidneys can excrete it or hold on to it to keep the balance between acid and base.

  • Star-SHL uses 20 - 31 mmol/l for bicarbonate, Unilabs 22.0 - 29.0 mmol/l, Certe 24 - 28 mmol/L and Diagnostiek voor U 21 - 28 mmol/L.
  • According to the NVKC, a raised bicarbonate together with a high pH fits a metabolic alkalosis, with prolonged vomiting among the possible causes.
  • According to the NVKC, a lowered bicarbonate together with a low pH fits a metabolic acidosis, with diabetes and serious kidney problems among the possible causes.

Bicarbonate: what Dutch laboratories use

There is no nationally agreed reference value; this is what individual laboratories publish.

The upper limit runs from 28 mmol/l at Certe to 31 mmol/l at Star-shl.

Reference ranges by group, in mmol/l
Star-shl · Everyone 20–31 mmol/l
20 31
Unilabs · Everyone 22–29 mmol/l
22 29
Certe · Everyone 24–28 mmol/L
24 28
Diagnostiek voor U · Everyone 21–28 mmol/L
21 28
0 34.1 mmol/l

Source: Star-shl

Source: Unilabs

Source: Certe

Source: Diagnostiek voor U

Each value as the laboratory itself publishes it, retrieved in 2026.

Bicarbonate: what this test measures

A bicarbonate test measures the amount of HCO3- in the blood in mmol/L, and when complications of diabetes are suspected the NVKC also names a blood gas test.

Bicarbonate: why this value matters

Bicarbonate matters because, according to the NVKC, a metabolic acidosis, a low pH with a lowered HCO3-, has diabetes as a possible cause.

Bicarbonate: how the blood test works

Referral
No GP referral needed. After the order we arrange the referral through ZorgDomein, within one business day; orders after 17:00 or at the weekend start on the next business day. ZorgDomein emails a barcode, and that barcode is what the draw site needs.
The draw
A blood draw from a vein in the arm, at a partner laboratory's draw site. No home kit, no finger prick.
Where
650+ draw sites run by independent laboratories across the Netherlands. Draw sites

Bicarbonate: when is testing worthwhile?

According to MedlinePlus, a CO2 blood test, with bicarbonate as its main form, may be ordered for symptoms of an electrolyte imbalance, which may include vomiting or diarrhoea over a long period, weakness, fatigue, confusion or trouble breathing.

Bicarbonate: symptoms of a high or low value

Low Levels

According to MedlinePlus, diabetic ketoacidosis, a complication of type 1 and type 2 diabetes, is one of the conditions of which too little CO2 in the blood may be a sign, like shock; at Diagnostiek voor U normal bicarbonate starts at 21 mmol/L, at Star-SHL at 20 mmol/l.

High Levels

A bicarbonate above Diagnostiek voor U's 28 mmol/L or Star-SHL's 31 mmol/l can, according to MedlinePlus, be a sign of a metabolic alkalosis, in which the body may lose acid through, for example, vomiting or dehydration.

Bicarbonate: causes of a low or high value

What lowers the value

  • Diabetic ketoacidosis

    Too little CO2 in the blood may be a sign of diabetic ketoacidosis, a complication of type 1 and type 2 diabetes.

  • Serious kidney problems

    Serious kidney problems can be a cause of a metabolic acidosis: a low pH together with a lowered HCO3- in the blood.

  • Long-lasting diarrhoea

    Long-lasting diarrhoea is one of the possible causes of a metabolic acidosis, in which there can be too little CO2 in the blood.

  • Hyperventilation

    Too little CO2 in the blood may be a sign of a respiratory alkalosis, which comes from a lung or breathing problem, including hyperventilation: rapid, deep breathing.

  • A tube opened before analysis

    After the collection tube is opened, the bicarbonate concentration falls by about 6 mmol/L per hour; the tube must stay closed until analysis.

What raises the value

  • Prolonged vomiting

    Prolonged vomiting, with loss of acid from the stomach, can cause a metabolic alkalosis: a high pH together with a raised HCO3- in the blood.

  • An overdose of bicarbonate

    An overdose of bicarbonate can be a cause of a metabolic alkalosis with a raised HCO3-.

  • Cushing's syndrome

    Too much CO2 in the blood can be a sign of Cushing's syndrome.

  • Lung diseases

    Too much CO2 in the blood can be a sign of lung diseases.

Bicarbonate: lifestyle and this value

With a low bicarbonate, tell your GP whether you have diabetes, because according to MedlinePlus too little CO2 in the blood may be a sign of diabetic ketoacidosis.

Bicarbonate: frequently asked questions

Can long-lasting diarrhoea lower bicarbonate?

Yes, according to MedlinePlus long-lasting diarrhoea is one of the possible causes of a metabolic acidosis, and according to the NVKC a metabolic acidosis is a low pH together with a lowered HCO3- in the blood.

Bicarbonate: sources

  1. Star-shl, Labbepalingen (referentiewaarden per bepaling), star-shl.nl, geraadpleegd 2026-10-01 (retrieved 2026) star-shl.nl
  2. Unilabs, Bepalingenklapper (referentiewaarden per bepaling), bepalingenklapper.nl, geraadpleegd 2026-10-01 (retrieved 2026) bepalingenklapper.nl
  3. Certe, Bepalingenwijzer (referentiewaarden per bepaling), bepalingenwijzer.certe.nl, geraadpleegd 2026-10-01 (retrieved 2026) bepalingenwijzer.certe.nl
  4. Diagnostiek voor U, eLabgids (Referentiewaarden DvU), diagnostiek.getincontrol.eu, geraadpleegd 2026-10-01 (retrieved 2026) diagnostiek.getincontrol.eu
  5. MedlinePlus, Carbon Dioxide (CO2) in Blood, medlineplus.gov, geraadpleegd 2026-10-19 (retrieved 2026) medlineplus.gov
  6. NVKC, Alles over testen: Bloedgassen, allesovertesten.nl, geraadpleegd 2026-10-19 (retrieved 2026) allesovertesten.nl

Tests with related values

These panels measure values from the same category as this marker.

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Your starting point before the first injection: blood sugar, cholesterol, pancreas, liver, kidneys, thyroid and nutrients in one measurement.

Insulin (Fasting) ALT (Alanine Aminotransferase) TSH (Thyroid Stimulating Hormone) AST (Aspartate Aminotransferase) HDL Cholesterol HbA1c (Glycated Hemoglobin) Bilirubin (Total) ApoB (Apolipoprotein B) Vitamin B12 Ferritin Potassium Sodium Glucose (Fasting) Total Cholesterol Albumin Lipase Creatinine Vitamin D (25-OH) Triglycerides Bilirubin (Direct) Bilirubin (Indirect) HOMA-IR eGFR (Estimated Glomerular Filtration Rate) LDL Cholesterol Cholesterol/HDL Ratio Non-HDL Cholesterol LDL/HDL Ratio
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GLP-1

GLP-1 Extended Panel

The 6-month measurement: everything from the check-in plus insulin, ApoB and your nutrients — especially relevant if you have been eating much less for a while.

Insulin (Fasting) ALT (Alanine Aminotransferase) AST (Aspartate Aminotransferase) HDL Cholesterol HbA1c (Glycated Hemoglobin) ApoB (Apolipoprotein B) Vitamin B12 Ferritin Potassium Sodium Glucose (Fasting) Total Cholesterol Albumin Lipase Creatinine Vitamin D (25-OH) Triglycerides HOMA-IR eGFR (Estimated Glomerular Filtration Rate) LDL Cholesterol Cholesterol/HDL Ratio Non-HDL Cholesterol LDL/HDL Ratio
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Bicarbonate

€10,-